1. Field of the Invention
The present invention relates to lens modules and cameras and, more particularly, to a lens module that can prevent a plastic lens therein from being affected by ultraviolet light, and a camera employing the lens module.
2. Description of Related Art
Generally, image pick-up devices such as charge coupled devices (CCD) or complementary metal oxide semiconductors (CMOS) used in, for example, cameras, react to light even in the near-infrared region beginning at a wavelength of about 700 nm and in the infrared (IR) region. However, light in the near-infrared and IR regions causes crosstalk that reduces a signal-to-noise ratio of an image pick-up device and thereby deteriorating the device's reproduction ability. In order to prevent such reaction and crosstalk, IR cut filters that block light in the near-infrared and IR regions are assembled in lens modules implemented in conventional cameras.
However, in a conventional lens module, the IR cut filter usually is assembled as the last part for the lens module by using ultraviolet (UV) glue on a spacer. The use of UV glue has adhesion and reliability problems. Also, a plastic lens in the lens module may be affected by UV light in sunlight, or by UV light used in UV curing processes. Many plastic lenses turn yellow with long-term exposure to UV light.
What is needed, therefore, is a lens module which can prevent plastic lenses from being affected by UV light.